list_pinned_messages

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden. It implies a read via 'List' but never states that it is non-mutating, whether it requires specific permissions, or any pagination/limit behavior. The only returned-value note overlaps with the existing output schema, so it adds little.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short, front-loaded sentences with no filler, and the purpose statement leads. The middle sentence about return content is partially redundant given the output schema, which keeps it short of a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter read tool with an output schema documenting returns, the description covers purpose and parameter sourcing adequately. The missing piece is sibling-based usage guidance, which is not critical for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate for the single required chat_id parameter. Telling the agent to obtain chat_id via list_chats adds real meaning beyond the schema, but format/validity details are left unspecified.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource ('List pinned messages in a chat'), which is clearly distinct from the mutation siblings pin_message and unpin_message. It doesn't explicitly contrast itself with list_chat_messages or search_messages, but the scope is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It supplies one prerequisite pointer — 'Use list_chats to get the chat_id' — which is genuinely useful for obtaining the required parameter. However, there is no guidance on when to prefer this over siblings like list_chat_messages or search_messages, so usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.